The invention relates to a lamp unit for motor vehicles and a method of making the lamp unit.
EP 0791 911 A2 discloses a lamp unit that has a light source, a reflector, and a plano-convex lens whose planar side faces the light source. An emblem is introduced as identification symbol on the planar side.
The emblem is easily visible to a viewer only when the viewer is situated at least approximately centrally in front of the lamp unit. When the viewer views the lamp unit at an oblique angle, the emblem becomes distorted or unclear.
It is therefore an object of the invention to create a lamp unit whose identification symbol is clearly visible over a substantially larger viewing angle.
This object is achieved by means of a lamp unit described hereinafter.
In accordance with the invention, a lamp unit is shaped as a projection headlamp and has a projection lens that is constructed in the shape of a spherical segment such that an identification symbol arranged on its planar side can be seen without distortion and clearly over a relatively large viewing angle. The arrangement of the identification symbol on the planar side permits the identification symbol to be applied in a way that is relatively simple and free from distortion. The identification symbol may be applied by means of, for example, a sand-blasting method. In order for the viewer to have an equally good view of the identification symbol over a large angular range, it is preferable to arrange the symbol in a central region of the planar side. In addition, an identification symbol, centrally arranged in a suitably small region, does not appreciably impair the light passing through the lens. It is clear that the lens in the shape of a spherical segment has substantial thickness and curvature, and the identification symbol can be seen without distortion even at an oblique viewing angle.
In this case, the projection lens can be arranged in an area behind a transparent cover plate that is adapted, for example, to the front end of a motor vehicle.
If the light exit aperture of the lens is surrounded by a circumferential trim ring which has a reflecting surface opposite the convex side of the lens, the reflected daylight falling into the projection lens reproduces the identification symbol particularly effectively. In this case, the reflecting surface of the trim ring can be colored so as to reflect in a silver-frosted fashion or in some other way, such that the identification symbol is reproduced with a color component of the color of the reflecting surface.
In a preferred embodiment, if the diameter of the central region is approximately ¼ to ⅓ of the lens diameter, the identification symbol may not appreciably impair the light passing through the projection lens.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.